Avalanche Forecast

Archived

Apr 8th, 2015–Apr 9th, 2015

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kootenay Boundary.

Daytime warming will be driving the avalanche danger on Thursday. Watch for conditions that change with aspect, elevation and time of day.For details on how we issue Spring Danger Ratings, check out the latest Forecaster Blog.

Confidence

Fair - Due to the number of field observations

Weather Forecast

On Thursday and Friday morning, a dry ridge will maintain sunny skies and strong diurnal temperatures swings. Increased cloud should develop throughout the day on Friday. By Friday evening, we can expect light snow (up to 10cm) and cooler temperatures which should continue into Saturday. Daytime freezing levels should hover around 2300m on Thursday, 1800m on Friday and about 1500m on Saturday. Ridgetop winds will be light on Thursday, and then become strong from the southwest with Friday and Saturday's system.

Avalanche Summary

Observations are becoming more limited as we enter into spring. If you're out in the mountains, please consider posting your observations to our webpage using the Mountain Information Network. With freezing levels rising and lots of sun expected on Thursday, lots of natural sluffing is expected from steep sun-exposed slopes. Cornices will become weaker and may fail naturally. Thin wind slabs may also be sensitive to human triggering on isolated high elevation, lee slopes.

Snowpack Summary

Melt-freeze surface conditions exist on sun-exposed slopes. On shaded slopes, 10-20cm of recent snow overlies a thick supportive melt-freeze crust. At higher elevations these accumulations may have been blown around by variable winds and thin wind slabs may exist on a variety of aspects. The mid-March crust/facet complex is buried around 50cm below the surface. This layer is generally considered dormant, although it could be reactivated in isolated terrain by warm temperatures forecast for the week. The mid and lower snowpack are strong and well settled.

Problems

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.